The present invention regards protecting a coated work-piece during its manufacture or reconfiguration. More specifically the present invention regards reducing the probability of damaging the coating of a work-piece during the work-piece""s manufacture by managing or regulating the temperature of the coating.
Articles of manufacture are regularly coated for numerous and varying reasons. For example, they may be coated to protect them from the intrusive handling they may be subjected to during their manufacture or to protect them from the environmental effects they may endure after they are manufactured. In either of these, as well as in others, damage to the coating of a work-piece, resulting from the handling or reconfiguration of the work-piece, is an unwanted result.
When the coating of a work-piece becomes scratched or otherwise damaged during the work-piece""s manufacture, the scratches can promote the deterioration of the work-piece by exposing the work-piece""s surface to its surroundings. Should the work-piece, upon its completion, be employed in a corrosive environment, the exposed surface of the finished product would be more vulnerable to corrosion than if its coating were completely intact. Moreover, the scratches and inconsistencies in the coating of the work-piece may also reduce the effectiveness of the finished product. For example, should the coating be used to uniformly deliver some type of releasable substance, inconsistencies in the surface of the coating can foster uneven and inconsistent delivery of the releasable substance to the deployed product""s final surroundings.
An expandable coated stent is one specific example of the coated work-pieces described above. Expandable stents are tube-like medical devices designed to support the inner walls of a vessel within the body of a patient. These stents are typically positioned within a targeted lumen of the body and then expanded to provide internal support for the lumen. These stents may be self-expanding or, alternatively, may require external forces to expand them. In either case they are typically deployed through the use of a catheter of some kind. These catheters typically carry the stent at their distal ends. In use, a practitioner will position the catheter""s distal end near the target area of the lumen. Once properly positioned the stent will be deployed by the practitioner such that it comes to rest near or in direct contact with the inner walls of the lumen. There, the stent will remain to provide support for the lumen.
Due to the interaction of the stent with the inner walls of the lumen, stents have been coated to enhance their effectiveness. These coatings may, among other things, be designed to facilitate the acceptance of the stent into its applied surroundings or to enable the delivery of therapeutic to the lumen and its surroundings. Thus, when the coating is haphazardly applied or has somehow been removed during the stent""s manufacture, both the stent""s longevity and its effectiveness can be reduced.
The coatings on the stent may be applied at various times during its life cycle including its manufacture, its placement onto the distal end of the delivery catheter, and contemporaneous with the medical procedure. At each of these times the coating may be at risk of being scratched, damaged or otherwise removed from the surface of the stent. For example, during their manufacture, stents are often crimped onto the distal end of a delivery catheter. This crimping process requires the exertion of significant forces against the coating of the stent to facilitate a reduction in the stent""s circumference to secure it to the catheter. During this crimping, the mechanical arms of a crimper may come in contact with the coating of the stent as they reduce the diameter of the stent. This compressive contact can scratch, indent, wipe-off or otherwise breach the integrity of the coatingxe2x80x94an undesirable result.
Thermal regulation of a coated work-piece during the reconfiguration of the work-piece is provided. One method embodying the invention comprises placing an externally coated reconfigurable work-piece, whose hardness has been temporarily modified to resist damage during the reconfiguration of the work-piece, into a reconfiguration chamber of a reconfiguration apparatus and reconfiguring the work-piece from a first configuration to a second configuration via physical communication between the external coating of the reconfigurable work-piece and the reconfiguration apparatus.
An apparatus embodying the invention includes a reconfiguration chamber, a nozzle in fluid communication with the reconfiguration chamber, a regulator in fluid communication with the nozzle, the regulator adapted to regulate the flow of a thermal transfer fluid, and a controller in communication with the regulator. Wherein the controller is adapted to send control signals to the regulator to maintain the surface temperature of the external coating of the reconfigurable work-piece within a predetermined temperature range and wherein the predetermined temperature range affords a predetermined minimum hardness for the external coating of the reconfigurable work-piece.